1. Field of the Invention
The invention relates to a bioreactor having a container, a shaft housing for guiding a shaft through a wall, a stirrer connected to the shaft in the interior of the container, and a drive arranged outside the container and connectable to the shaft, said shaft being mounted in the shaft housing via at least one ball bearing and being sealed in relation to the shaft housing by at least one seal.
2. Description of the Related Art
Bioreactors having a container with a flexible wall are being increasingly used, particularly as disposable bioreactors, in pharmacy and biotechnology.
US 2006/0280028 A1 discloses a bioreactor having a container with a flexible wall, through which wall a shaft is guided in order to drive a stirrer arranged in the interior of the container. A shaft housing is connected to the flexible wall via a sealing flange. The shaft is mounted in the shaft housing via two ball bearings. The shaft has a flat radial sealing collar, which is arranged in a recess of the shaft housing. The outer annular end face directed away from the interior of the container is sealed in relation to a bottom surface of the recess by a lip seal. The inner annular end face of the collar, directed toward the interior of the container, is sealed in relation to the locked floor part of the shaft housing by two coaxially arranged lip seals.
A disadvantage of the above is that the structure of the shaft housing, in conjunction with the seals, is quite complicated and cost-intensive and also takes up quite a large volume.
Moreover, US 2005/0239199 A1 discloses a bioreactor having a container with a flexible wall, in which container a shaft is guided rotatably through the flexible wall into the interior of the container by way of a shaft housing connected to the flexible wall. In the shaft housing opening directed toward the interior, the shaft is guided by a radially protruding annular disk which is arranged in said opening and which is sealed in relation to a recess of the shaft housing by two coaxially arranged lip seals.
This device also has the abovementioned disadvantages.
EP 1 156 242 A2 discloses a radial shaft seal with two sealing lips, in which the sealing lip lying on the hydraulic side is pressed by an annular helical spring onto the shaft that is to be sealed. A disadvantage of this is that these seals are designed as seals running in hydraulic liquid, or at least as lubricated seals, in which the space between the sealing lips is used as a lubricant depot.
The object of the present invention is therefore to make available a bioreactor having a container in which the shaft is guided through a wall, which is flexible for example, by way of a compact structure and in a simple and inexpensive manner and yet in a liquid-tight and gas-tight manner.